Cisco CCNA NAT for IPv4 5

Question 1

Which statement about NAT and IPv6 is most accurate from a CCNA perspective?

Accepted Answer

IPv6 was designed with sufficient address space to eliminate the need for NAT

Answer

IPv6's 128-bit address space provides enough unique addresses for every device globally, removing the address-conservation motivation that drove widespread IPv4 NAT adoption.

Question 2

A 'show ip nat translations' output shows entries with 'Pro' as '---'. What type of traffic do these entries represent?

Accepted Answer

Non-TCP/UDP traffic such as GRE or other IP protocols

Answer

The '---' protocol field in NAT translation entries indicates non-TCP/UDP traffic (such as GRE tunnels or other IP protocols) that PAT cannot differentiate by port.

Question 3

What is the purpose of the 'ip nat translation timeout' command?

Accepted Answer

Adjusts how long idle dynamic NAT entries are kept before removal

Answer

'ip nat translation timeout [seconds]' configures the idle timeout for dynamic NAT translations before the router removes them from the table.

Question 4

Which feature allows a Cisco router to apply NAT based on the destination address rather than the source address?

Accepted Answer

ip nat inside destination

Answer

'ip nat inside destination' translates the destination IP of packets arriving on the inside interface, commonly used for load-balancing to multiple internal servers.

Question 5

An administrator notices that after configuring NAT, internal users cannot reach the internet. The ACL for NAT is 'permit 192.168.10.0 0.0.0.255'. Users are on 192.168.20.0/24. What is the problem?

Accepted Answer

The ACL does not match the users' subnet, so their traffic is not being translated

Answer

The ACL only permits 192.168.10.0/24; users on 192.168.20.0/24 don't match, so their source addresses are never translated and packets are dropped or sent untranslated.

Cisco CCNA Practice Test

Cisco CCNA Practice Test

Cisco CCNA NAT for IPv4 5